Sealing device and rotation detector

ABSTRACT

A pulser ring and a second seal ring are separately formed. When a multipolar magnetic rotor of the pulser ring is bonded to an outer circumferential face of an outer cylindrical portion of an annular core portion, the multipolar magnetic rotor is opposed to a magnetic sensor in the radial direction. Due to the above structure, the multipolar magnetic rotor can be strongly supported by an outer cylindrical portion of the annular core portion. Therefore, even when a rotary centrifugal force is given to the multipolar magnetic rotor, it can not be swung in the radial direction. Accordingly, an interval of the multipolar magnetic rotor and the magnetic sensor in the radial direction, which are opposed to each other, can be maintained constant irrespective of an intensity of the centrifugal force.

BACKGROUND OF THE INVENTION

The present invention relates to a sealing device in which two seals arecombined with each other and into which a magnetic sensor and pulserring to be used as a rotation detector are incorporated.

In the case of applying the above sealing device to a rolling bearing,the magnetic sensor is attached to a seal ring which is attached to abearing ring on the stationary side, and the pulser ring is attached toa seal ring which is attached to a bearing ring on the rotary side.After a piece of rubber containing magnetic powder has been bonded tothe seal ring attached to the bearing ring on the rotary side, N-polesand S-poles are alternately magnetized in the circumferential direction.Concerning this constitution, refer to JP-A-10-132603.

In the above example, since the pulser ring is directly bonded to theseal ring, the pulser ring is affected by a centrifugal force ofrotation and swung in the radial direction. Accordingly, there is apossibility that an interval between the pulser ring and the magneticsensor, which are opposed to each other, fluctuates in the radialdirection.

The official gazette of JP-A-10-160744 discloses a sealing devicereferred to as a pack seal in which two seal rings are combined witheach other. Either of these seal rings is composed in such a manner thata lip made of rubber is bonded to a metallic ring. In the case where therolling bearing is of the inner ring rotation type, the magnetic sensoris attached to the first seal ring attached to an outer ring which isnot rotated, and the pulser ring is attached to the second seal ringattached to an inner ring which is rotated.

In the above conventional example, the metallic ring is interposedbetween the magnetic sensor face and the pulser ring face which areopposed to each other. Due to this structure, it is impossible to reducean interval between them exceeding a predetermined limit. Further, whenlines of magnetic force generated by the pulser ring penetrate themetallic ring, an eddy current is generated. This eddy current mayaffect a detecting action of the magnetic sensor. Therefore, in order tofurther enhance the detecting accuracy of the magnetic sensor, the abovestructure leaves room for improvements.

The official gazette of JP-A-2001-21576 discloses a device in which theseal device is applied to a rolling bearing of the inner ring rotationtype. The magnetic sensor is attached to one end face of the outer ringwhich is not rotated, and the magnetic ring is attached to one end faceof the inner ring, which is rotated, via a support member. The supportmember is provided with a cylindrical portion and a flange portionextending inward in the radial direction. The magnetic ring is bonded toan outer circumferential face of the cylindrical portion of this supportmember. The magnetic ring is made of rubber containing magnetic powder,and N-poles and S-poles are alternately magnetized in thecircumferential direction. A detection face of the magnetic sensor isperpendicular to a face to be detected of the magnetic ring.

In the above conventional example, since the detection face of themagnetic sensor is perpendicular to the face to be detected of themagnetic ring, when the position of the magnetic sensor and that of themagnetic ring are shifted from each other in the axial direction, adistance between the detecting face of the magnetic sensor and the faceto be detected of the magnetic ring is extended. Therefore, it isnecessary to increase the size of the piece of rubber containingmagnetic powder so as to increase an intensity of the magnetic force.Further, it is necessary to employ a more sensitive magnetic sensor.Accordingly, the size of the rotation detector is increased and themanufacturing cost is raised.

The official gazette of the French Patent Publication No. FR2 574 501-A1discloses a device in which a sealing device is applied to a rollingbearing. A magnetic sensor is attached to a seal ring attached to abearing ring on the stationary side, and a pulser ring is attached to aseal ring attached to a bearing ring on the rotary side. In this case,the pulser ring is made of rubber containing magnetic powder andmagnetized. One portion of the pulser ring comes into contact with aseal portion made of rubber provided in the seal ring and composes aportion of a tightly sealing portion for tightly sealing the inside ofthe bearing.

In the above conventional example, one portion of the pulser ringslidably coming into contact with the seal portion is made of rubbercontaining magnetic powder. Therefore, the magnetic powder acts asgrinding particles, which cause abrasion in the opponent (the sealingportion on the stationary side) coming into contact with the pulserring.

SUMMARY OF THE INVENTION

In view of the above problems caused in the conventional example, it isan object of the present invention to prevent the deterioration of thedetecting accuracy of a magnetic sensor provided in a sealing device andenhance the detecting accuracy.

It is another object of the present invention to stably exhibit thesealing property of a sealing device over a long period of time.

In order to accomplish the above objects, the constitution of thepresent invention is characterized as follows.

(1) A sealing device comprising:

a first seal ring that is fixed to an outer ring member;

a second seal ring that is fixed to an inner ring member capable ofrelatively, coaxially rotating with respect to the outer ring member;and

a magnetic sensor that is attached to the first seal ring,

wherein the second seal ring includes:

-   -   a metallic ring that is engaged with an outer circumference of        the inner ring member;    -   a lip that is bonded to the metallic ring, and comes into        contact with the first seal ring; and    -   a pulser ring that is provided in the metallic ring so that the        pulser ring can be opposed to the magnetic sensor in the radial        direction and is detected by the magnetic sensor,

wherein the pulser ring includes:

-   -   an annular core portion that includes an inner cylindrical        portion provided on an outer circumference of the metallic ring,        an outer cylindrical portion arranged coaxially with the inner        cylindrical portion, and an annular plate portion for connecting        the inner cylindrical portion with the outer cylindrical        portion; and    -   a multipolar magnetic rotor, in which N-poles and S-poles are        alternately arranged in the circumferential direction, and which        is bonded to the outer cylindrical portion.

(2) A sealing device according to (1), wherein the lip is made of rubberor resin.

(3) A sealing device according to (1), wherein the multipolar magneticrotor is made of material on the basis of rubber or resin containingmagnetic powder.

(4) A sealing device according to (1), wherein the inner cylindricalportion and the outer cylindrical portion are arranged inside the widthin an axial direction defined by the first and the second seal ring.

(5) A sealing device according to (1), wherein a portion of themultipolar magnetic rotor fills a gap formed between the annular coreportion and the metallic ring.

(6) A rotary detector comprising:

a sensor assembling body that is fixed to a outer ring member; and

a pulser ring that is fixed to an inner ring member capable ofrelatively, coaxially rotating with respect to the outer ring member, isto be detected by the sensor assembling body, and is opposed to thesensor assembling body in the radial direction,

wherein the sensor assembling body includes:

-   -   an annular ring that includes a cylindrical portion;    -   a magnetic sensor that is molded out of an outer body made of        resin, and is arranged at a predetermined position on a outer        circumferential side of the cylindrical portion; and    -   a window that is opened in a radial direction and is formed in a        region of the metallic ring corresponding to the region in which        the magnetic sensor is arranged.

(7) A rotary detector according to (6), wherein the pulser ringincludes: an annular core portion having a cylindrical portion; and amultipolar magnet rotor that is bonded to an outer circumference of thecylindrical portion of the annular core portion and is opposed to themagnetic sensor in the radial direction.

(8) A rotary detector according to (6), wherein the sensor assemblingbody is press-fitted onto an inner circumferential face of the outerring member, and the pulser ring is press-fitted onto an outercircumferential face of the inner ring member.

(9) A rotary detector according to (6), wherein the magnetic sensor isexposed from the resin outer body, and one face of the magnetic sensoris on the same face as the face of the window

(10) A sealing device comprising:

a first seal ring that is fixed to an outer ring member;

a second seal ring that is fixed to an inner ring member capable ofrelatively, coaxially rotating with respect to the outer ring member;and

a magnetic sensor that is attached to the first seal ring,

wherein the second seal ring includes a pulser ring that is detected bythe magnetic sensor and is provided in the metallic annular ring so thatthe second seal ring can be opposed to the magnetic sensor in a radialdirection,

wherein the pulser ring includes; an annular core portion attached to anouter circumference of the second seal ring; and a multipolar magneticrotor provided on an outer circumferential face of the cylindricalportion of the annular core portion, and

wherein N-poles and S-poles are alternately arranged in the multipolarmagnetic rotor in a circumferential direction, and the multipolarmagnetic rotor emits lines of magnetic force, which loop between themagnetic poles, in the radial direction onto the magnetic sensor side.

(11) A sealing device according to (10), wherein N-poles and S-poles arealternately formed and arranged in the circumferential direction of themultipolar magnetic roller by magnetizing a base of rubber or resincontaining magnetic powder in the radial direction of the multipolarmagnetic rotor.

(12) A sealing device comprising:

a first seal ring that is fixed to an outer ring member;

a second seal ring that is fixed to an inner ring member capable ofrelatively, coaxially rotating with respect to the outer ring member;and

a magnetic sensor that is attached to the first seal ring,

wherein the second seal ring includes:

a metallic ring that is engaged with an outer circumference of the innerring member;

a lip that is bonded to the metallic ring, and comes into contact withthe first seal ring; and

a multipolar magnetic rotor that is provided in the metallic ring sothat the multipolar magnetic rotor can be opposed to the magnetic sensorin the radial direction, wherein the multipolar magnetic rotor includesN-poles and S-poles alternately arranged in the circumferentialdirection, a space being formed between the multipolar magnetic rollerand the first seal ring in the radial direction.

(13) A sealing device according to (12), wherein the second seal ringincludes an annular core portion engaged with an outer circumference ofthe metallic ring, and the multipolar magnetic rotor is bonded to anouter circumference of the annular core portion.

(14) A sealing device according to (12), wherein the multipolar magneticrotor and the lip are separately formed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing a rolling bearing device into which asealing device of the first embodiment of the present invention isincorporated.

FIG. 2 is an enlarged view showing the second sealing device illustratedin FIG. 1.

FIG. 3 is a front view showing the rotation detector illustrated in FIG.2.

FIG. 4 is a perspective view showing a model of the circumstances oflines of magnetic force emitted from the pulser ring illustrated in FIG.2.

FIG. 5 is a perspective view showing the first metallic ring illustratedin FIG. 2.

FIG. 6 is a view showing the second embodiment of the present invention,wherein the view corresponds to FIG. 2.

FIG. 7 is a schematic illustration in the case where a magnetic sensoris used as a sensor for detecting the normal and the reverse direction.

FIG. 8 is a view showing a detection signal outputted from the sensorfor detecting the normal and the reverse direction illustrated in FIG.7.

FIG. 9 is a view showing the third embodiment of the present invention,wherein the view corresponds to FIG. 2.

FIG. 10 is a view showing the sealing device illustrated in FIG. 9,wherein the view corresponds to FIG. 3.

FIG. 9 is a view showing the fourth embodiment of the present invention,wherein the view corresponds to FIG. 2.

FIG. 12 is a view showing the sealing device illustrated in FIG. 9,wherein the view corresponds to FIG. 3.

FIG. 13 is a view showing the fifth embodiment of the present invention,wherein the view corresponds to FIG. 2.

FIG. 14 is a view showing the sealing device illustrated in FIG. 9,wherein the view corresponds to FIG. 3.

FIG. 15 is a view showing the seventh embodiment of the presentinvention, wherein the view corresponds to FIG. 2.

FIG. 16 is a view showing the eighth embodiment of the presentinvention, wherein the view corresponds to FIG. 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS First Embodiment

FIGS. 1 to 5 are views showing the first embodiment of the presentinvention. In this embodiment, explanations are made into a case inwhich a sealing device of the present invention is incorporated into therolling bearing device 1 used for a drive wheel of an automobile. InFIG. 1, the left of the rolling bearing device 1 is the outer side ofthe vehicle, and the right of the rolling bearing device 1 is the innerside of the vehicle.

The inner shaft member 3 is pivotally supported by the outer ring member2, which is fixed not to be rotated, round the axis via two rows ofrolling elements (for example, balls) which are respectively arranged atregular intervals on the circumference by the crown-shaped cages 6 a, 6b.

On the outer circumferential face of the outer ring member 2, the flangeportion 21 extending outside in the radial direction is formed. When theflange portion 21 is fixed to the knuckle 9, which is a portion of thevehicle body, by the bolts 10, the outer ring member 2 is fixed beingnot rotated.

The inner shaft member 3 includes: an inner shaft 31; and an inner ring32 used for a single row angular ball bearing. The inner ring 32 isattached to the inner side of the barrel portion of the inner shaft 31.When an end portion of the inner shaft 31 on the inner side of thevehicle is rolling-calked outward in the radial direction, the innerring 32 can be integrated with the inner shaft 31.

Two rows of rolling elements 4, 5 are interposed between two racewaytracks, which are provided on the inner circumferential face of theouter ring member 2 in the axial direction, and the raceway track, whichis provided on the outer circumferential face of the inner shaft 31 andthe raceway track which is provided on the outer circumferential face ofthe inner ring 32.

On the outer circumferential face of the inner shaft 31, on the outerside of the vehicle, the flange portion 34 extending outward in theradial direction is integrally formed. Although not shown in thedrawing, a brake disk and a wheel are attached to the flange portion 34.The inner shaft 13 integrally formed in the bowl-shaped outer ring 12 ofa constant velocity joint (CVJ) is spline-engaged in the central hole ofthe inner shaft 31. When the nut 14 is screwed to the outer side endportion of this shaft 13, the bowl-shaped outer ring 12 is integratedwith the inner shaft member 3.

On both sides of the space formed between the outer ring 2 and the innershaft member 3 in the axial direction, the first sealing device 7 andthe second sealing device 8 are attached. Both the sealing devices 7, 8prevent the lubricant from leaking outside from the annular space 11 inwhich the rolling elements 4, 5 are arranged. At the same time, both thesealing devices 7, 8 prevent the muddy water from getting into theannular space 11 from the outside.

Although the detail are not shown in the drawing, the first sealingdevice 7 arranged on the outer side of the vehicle is composed in such amanner that a lip made of rubber, which comes into slide contact withthe inner shaft 31, is bonded to a metallic ring inwardly attached theouter ring 2.

As shown in FIG. 2, the second sealing device 8 arranged on the innerside of the vehicle is composed in such a manner that the first sealring 81 and the second seal ring 82 are combined with each other. Thesecond sealing device 8 is referred to as a pack seal. As a rotationdetector for detecting a state of rotation of the inner shaft member 3(the inner shaft 31 and the inner ring 32) such as a phase of rotation,rotation speed, number of rotations and direction of rotation, themagnetic sensor 15 and the pulser ring 16 are incorporated into thissecond sealing device 8. The structure of the second sealing device 8will be explained in detail as follows.

The first seal ring 81 is attached to the outer ring member 2. The firstseal ring 81 is composed in such a manner that the main lip 84 and theauxiliary lip 85 are attached to the first metallic ring 83. The firstmetallic ring 83 includes: a cylindrical portion 83 a; and a flangeportion 83 b extending from the inner end of the cylindrical portion 83a in the axial direction to the inside in the radial direction. The mainlip 84 and the auxiliary lip 85 are bonded to an inner circumference ofthe flange portion 83 b by vulcanization. The outer body 17 made ofresin of a predetermined thickness is laminated on the entire outercircumference of the cylindrical portion 83 a in the first metallic ring83, and the magnetic sensor 15 is embedded in the outer body 17 made ofresin. At a predetermined position on the circumference of the outerbody 17 made of resin, the female type connector 20 for connecting themagnetic sensor 15 with the harness (not shown), which is connected tothe electronic circuit of the vehicle body, is integrally formed underthe condition that the female type connector 20 protrudes outward in theradial direction.

In this connection, in the region in which the magnetic sensor 15 isarranged in the cylindrical portion 83 b of the first metallic ring 83,as shown in FIG. 5, the window 83 c open to the inside and outside inthe radial direction is provided. The size and shape of this window 83 care larger than the size and shape of the magnetic sensor 15 when theview is taken in the radial direction. Alternatively, the size and shapeof this window 83 c are substantially the same as the size and shape ofthe magnetic sensor 15 when the view is taken in the radial direction.When the window 83 c is provided as described above, no metallic memberis interposed between the magnetic sensor 15 and the pulser ring 16. Inthis connection, the window 83 c is provided so that the window 83 c cannot reach a region in which the lip 87 of the second seal ring 82 in theradial direction slidably comes into contact in the first metallic ring83. As shown in FIG. 5, the magnetic sensor 15 is arranged so that thedetecting face of the magnetic sensor 15 can be on the same face as theface of the opening end of the window 83 c on the outer diameter side.Further, the outer body 17 made of resin is filled in the window 83 c.

The second seal ring 82 is attached to the inner ring 32. The secondseal ring 82 is composed in such a manner that the lip 87 in the radialdirection is attached to the second metallic ring 86. The secondmetallic ring 86 includes: a cylindrical portion 86 a; and a flangeportion 86 b formed at the outer end of the cylindrical portion 86 a inthe axial direction in such a manner that the flange portion 86 bextends outward in the radial direction. The lip 87 in the radialdirection is bonded to the outer circumference of the flange portion 86b by vulcanization. The pulser ring 16 is attached to this second sealring 82.

In this connection, the lips 84, 85, 87 are made of rubber such asnitrile butadiene rubber (NBR). However, the lips 84, 85, 87 may be madeof appropriate resin.

The pulser ring 16 is composed in such a manner that the multipolarmagnetic rotor 19 is bonded to the annular core portion 18. The annularcore portion 18 is composed in such a manner that the outer end side ofthe inner cylindrical portion 18 a in the axial direction and the outerend side of the outer cylindrical portion 18 b in the axial direction,which are coaxially arranged in the radial direction, are integrallyconnected with each other by the annular plate portion 18 c. Themultipolar magnetic rotor 19 is composed in such a manner that rubbersuch as hydride nitrile butadiene rubber (H-NBR) or resin containingmagnetic powder is bonded to an outer circumferential face of the outercylindrical portion 18 b of the annular core portion 18 byvulcanization, and magnetization is conducted in the radial direction sothat N-pole and S-poles can be alternately arranged in thecircumferential direction. Between the multipolar magnetic rotor 19 andthe first metallic ring 83, a space is provided in the radial directionso that the multipolar magnetic rotor 19 can not contacted with thefirst metallic ring 83. As shown in FIGS. 3 and 4, this multipolarmagnetic rotor 19 emits lines of magnetic force to the outside whichloop the magnetic poles adjacent to each other in the circumferentialdirection. In this connection, raw material of the multipolar magneticrotor 19 is filled so that the outside of the annular plate portion 18 ccan be covered with the raw material, that is, the raw material isfilled into a gap formed between the annular core portion 18 and thesecond metallic ring 86. Therefore, it is possible to prevent theoutside water from getting into the engaging face on which the annularcore portion 18 and the second metallic ring 86 are engaged. It ispossible to avoid providing the portion into which the raw material ofthe multipolar magnetic rotor 19 is filled.

When the inner cylindrical portion 18 a of the annular core portion 18is engaged with the cylindrical portion 86 a of the second metallic ring86, the pulser ring 16 is attached to the second seal ring 82, and aface of the pulser ring 16 to be detected is opposed to the detectionface of the magnetic sensor 15 in the radial direction. Due to theforegoing, as shown in FIGS. 3 and 4, lines of magnetic force, whichloop the magnetic poles adjacent to each other in the circumferentialdirection in the multipolar magnetic rotor 19 of the pulser ring 16, areemitted to the outer diameter side and enter the detection face of themagnetic sensor 15.

In this connection, since the magnetic sensor 15 is attached to thefirst metallic ring 83, for example, the first metallic ring 83 is madeof non-magnetic material such as non-magnetic stainless steel (SUS304stipulated by JIS). Concerning the annular core portion 18, in order forthe annular core portion 18 to be formed into a magnetic passage forconverging the lines of magnetic force which are emitted from themultipolar core portion 18 to the inner diameter sides for example, theannular core portion 18 is made of magnetic material such as magneticstainless steel (SUS 430 stipulated by JIS). The outer body 17 made ofresin for molding the magnetic sensor 15 is made of non-magnetic resinsuch as polyphenylene sulfide (PPS), polybutylene terephthalate (PBT)and polyamide (PA), that is, the outer body 17 made of resin for moldingthe magnetic sensor 15 is made of engineering plastics. Although notshown in the drawing, lubricant such as grease is enclosed into a spacesurrounded by the first seal ring 81 and the second seal ring 82.

The second sealing device 8 is assembled as follows. The first seal ring81 and the second seal ring 82, to which the pulser ring 16 isintegrally attached, are temporarily assembled being tied to each other.The second metallic ring 86 is press-fitted into the shoulder portion 32a of the outer circumferential face of the inner ring 32, and the outerbody 17 made of resin of the first seal ring 81 is press-fitted into theshoulder portion 2 a of the inner circumferential face of the outer ring2. When the flange portion 17 a of the outer body 17 made of resin iscontacted with the end face 2 b of the outer ring 2 on the inner side ofthe vehicle, the first seal ring 81 is positioned. In the abovecondition, the main lip 84 and the auxiliary lip 85 of the first sealring 81 are made to come into contact with an outer circumferential faceof the inner cylinder portion 18 a of the annular core portion 18, andthe lip 87 in the radial direction of the second seal ring 82 iscontacted with the inner circumferential face of the cylindrical portion83 a of the first metallic ring 83. Since the lip 87 in the radialdirection of the second seal ring 82 is arranged outside the pulser ring16, it is possible to prevent the pulser ring 16 from being stained withdust. Therefore, the deterioration of accuracy of detection can beavoided. Further, since the pulser ring 16 is isolated from the rollingelements 5 and the raceway track by the main lip 84 and the auxiliarylip 85, it is possible to prevent the metallic abrasion powder, which isgenerated when the rolling elements 5 are rotated, from attaching to thepulser ring 16. Therefore, it is possible to prevent the deteriorationof accuracy of detection.

As explained above, in the second sealing device 8, the second seal ring82 and the pulser ring 16 are separately formed, and the multipolarmagnetic rotor 19 of the pulser ring 16 is bonded to an outercircumferential face of the outer cylindrical portion 18 b of theannular core portion 18. Therefore, the multipolar magnetic rotor 19 isstrongly supported by the outer cylindrical portion 18 b of the annularcore portion 18. Accordingly, even when a rotary centrifugal force isgiven to the multipolar magnetic rotor 19, it can not be swung in theradial direction. Due to the foregoing, an interval in the radialdirection of the magnetic sensor 15 and the multipolar magnetic rotor19, which are opposed to each other, can be maintained constantirrespective of an intensity of the centrifugal force. Accordingly, theaccuracy of detection can be enhanced. Further, it is possible toindividually, simply manufacture the pulser ring 16 and the second sealring 82. Therefore, the manufacturing cost can be reduced.

Especially, in the embodiment described above, since the innercylindrical portion 18 a and the outer cylindrical portion 18 b of theannular core portion 18 are arranged in the width in the axial directionof the first seal ring 81 and the second seal ring 82, it is unnecessarythat the width in the axial direction of the entire second sealingdevice 8 is extended. Accordingly, the entire device can be madecompact. When the width in the axial direction of the pulser ring 16 ismade maximum in the range of an interval in the axial direction of thefirst seal ring 81 and the second seal ring 82, as compared with a casein which the pulser ring 16 is bonded to the side of the annular plateportion 18 c of the annular core portion 18, an area in which the pulserring 16 and the magnetic sensor 15 are opposed to each other can beextended. Therefore, the detecting accuracy of the magnetic sensor 15can be enhanced as highly as possible.

In the second sealing device 8, no metallic members are interposedbetween the magnetic sensor 15 attached to the first seal ring 81 andthe multipolar magnetic rotor 19 of the pulser ring 16 attached to thesecond seal ring 82. Therefore, the lines of magnetic force generated bythe multipolar magnetic rotor 19 in the rotating operation pass throughthe window 83 c of the annular core portion 8. Accordingly, there is nopossibility that an eddy current is generated in the neighborhood of thedetecting face of the magnetic sensor 15 like the conventional example.Therefore, it is possible to prevent the occurrence of a conventionalproblem caused by the eddy current. Further, it is possible to reduce aninterval between the magnetic sensor 15 and the multipolar magneticrotor 19 which are opposed to each other. Due to the synergism, thedetecting accuracy of the magnetic sensor 15 can be enhanced.

In the second sealing device 8, the multipolar magnetic rotor 19 of thepulser ring 16 is bonded to an outer circumferential face of the outercylindrical portion 18 b of the annular core portion 18, and the linesof magnetic force, which loop the magnetic poles adjacent to each otherin the circumferential direction of the multipolar magnetic rotor 19,are emitted to the outer diameter side, that is, to the magnetic sensor15 side. Due to this structure, even when the position of the magneticsensor 15 and that of the pulser ring 16 are shifted from each other inthe axial direction, the lines of magnetic force emitted from themultipolar magnetic rotor 19 can easily get onto the detecting face ofthe magnetic sensor 15. Therefore, the lines of magnetic force emittedfrom the multipolar magnetic rotor 19 are seldom affected by thepositional deviation in the axial direction. Accordingly, the detectingaccuracy of the magnetic sensor 15 is not deteriorated.

In the second sealing device 8, the multipolar magnetic rotor 19 of thepulser ring 16 is provided separately from the lip 87 in the radialdirection of the second seal ring 82, and the lip 87 in the radialdirection is made of rubber into which magnetic powder, which couldbecome abrasion particles, is not mixed. Therefore, the first metallicring 83, which is an opponent of contact of the lip 87 in the radialdirection, can not be abraded. Due to the foregoing, the tightly sealingproperty can be exhibited over a long period of time.

For example, as shown in FIG. 7, the magnetic sensor 15 can be adetection sensor for detecting the normal and the reverse defectioncomposed of two sensor elements 22 a, 22 b such as hall elements ormagnetic resistance elements. Two sensors 22 a, 22 b are arrangedseparately from each other in the circumferential direction. Theinterval of the two sensors 22 a, 22 b is an interval (λ/4) at which theoutput phase of one sensor and that of the other sensor are shifted by90° from each other. In this case, λ is a magnetization pitch of themultipolar magnetic rotor 19. In this case, the magnetization pitch isdefined as a total length of the magnetization length in thecircumferential direction of N-pole and the magnetization length in thecircumferential direction of S-pole which is adjacent to N-pole. Whenone sensor element 22 a outputs a rectangular wave-form signal A shownin FIG. 8, the other sensor element 22 b outputs a rectangular wave-formsignal B, the phase of which is shifted from the phase of therectangular wave-form signal A by 90°. That is, when an opposing stateof the multipolar magnetic rotor 19 with respect to the detection sensorfor detecting the normal and the reverse direction is changed accordingto the rotating speed or the rotating direction of the multipolarmagnetic rotor 19, the phase and the period of the phase of therectangular wave-form signal, which is outputted from each sensorelement 22 a, 22 b of the detection sensor 15 for detecting the normaland the reverse direction, are changed. Therefore, when both therectangular wave-form signals are processed, the rotating phase, therotating speed, the number of rotations and the rotating direction canbe find.

Second Embodiment

FIG. 6 is a view showing the second embodiment of the present invention.As shown in FIG. 6, the multipolar magnetic rotor 19 of the pulser ring16 is bonded only onto the outer circumferential face of the outercylindrical portion 18 b of the annular core portion 18. That is, thepresent invention includes a constitution in which raw material of themultipolar magnetic rotor 19 is not filled to cover the outside of theannular plate portion 18 c. In this structure, this embodiment isdifferent from the first embodiment described before. In thisconnection, in this case, the window 83 c is not provided in the firstmetallic ring 83 illustrated in FIG. 6. In this case, since no portionis provided in which the raw material of the multipolar magnetic rotor19 is filled, the width of the outer cylindrical portion 18 b in theaxial direction can be extended. Therefore, the width of magnetizationof the multipolar magnetic rotor 19 can be extended and the detectingaccuracy can be enhanced.

Third Embodiment

FIGS. 9 and 10 are views showing the third embodiment. The magneticsensor 15 may be accommodated in the window 83 c as shown in FIGS. 9 and10.

Fourth Embodiment

FIGS. 11 and 12 are views showing the fourth embodiment. As shown inFIGS. 11 and 12, the detecting face of the magnetic sensor is may be onthe same face as the face of the opening end on the inner diameter sideof the window 83 c and exposed from the outer body 17 made of resin.According to this structure, an interval of the magnetic sensor 15 andthe multipolar magnetic rotor 19 can be reduced as small as possible,which is advantageous for enhancing the detecting accuracy of themagnetic sensor 15.

Fifth Embodiment

FIGS. 13 and 14 are views showing the fifth embodiment. As shown inFIGS. 13 and 14, the magnetic sensor 15 may be separate from the window83 c without being set into the window 83 c.

Sixth Embodiment

In the above embodiment, the window 83 c provided in the cylindricalportion 83 b of the first metallic ring 83 is a through-hole formed inthe radial direction. However, this window 83 c may be a cutout which isopen to the free end side of the cylindrical portion 83 b of the firstmetallic ring 83. In this case, it is preferable that the outer body 17made of resin is embedded in the cutout portion of the cylindricalportion 83 b and the inner circumferential face of the cylindricalportion 83 b is made to be on the same face in the circumferentialdirection so that a sliding face of the lip 87 in the radial directionof the second seal ring 82 can not be interrupted in the circumferentialdirection.

Seventh Embodiment

FIG. 15 is a view showing the seventh embodiment of the presentinvention. In this embodiment, the second metallic ring 86 is composedin such a manner that the outer cylindrical portion 86 c concentric withthe cylindrical portion 86 a is integrally connected to the outercircumference of the flange portion 86 b. The multipolar magnetic rotor19 is directly bonded by vulcanization onto the outer circumferentialface of the outer cylindrical portion 86 c. At the same time, the lip 87in the radial direction is attached onto the inner side of the vehicleof this multipolar magnetic rotor 19 in such a manner that the lip 87 isarranged being adjacent to the multipolar magnetic rotor 19. Even inthis embodiment, in the same manner as that of the embodiment shown inFIG. 2, the lip 87 in the radial direction is made of rubber or resinnot containing magnetic powder.

Eighth Embodiment

Still another embodiment of the second sealing device 8 is shown in FIG.16. In this embodiment, the second metallic ring 86 is composed in sucha manner that the size of the cylindrical portion 86 a in the axialdirection is decreased and the flange portion 86 b extending from theinside of this cylindrical portion 86 a to the outside in the radialdirection is integrally provided and the outer cylindrical portion 86 cis formed by bending the outer circumference of this flange portion 86 binto a lateral U-shape. The lip 88 in the axial direction coming intocontact with the flange portion 83 b of the first metallic ring 83 isbonded by vulcanization onto the inner side face of this flange portion86 b. The multipolar magnetic rotor 19 is directly bonded byvulcanization onto the outer circumferential face of the outercylindrical portion 86 c. Further, the main lip 84 and the auxiliary lip85 of the first seal ring 81 are made to directly come into contact withthe shoulder portion of the outer circumferential face of the inner ring32. Even in this embodiment, in the same manner as that of theembodiment shown in FIG. 2, the lip 87 in the axial direction is made ofrubber or resin not containing magnetic powder.

In the above embodiment, the present invention is applied to a rollingbearing device used for a drive wheel of an automobile. However, thesealing device of the present invention can be applied to a rollingbearing device used for an idle wheel of an automobile although notshown in the drawing. Further, the sealing device of the presentinvention can be applied to various uses.

1. A sealing device comprising: a first seal ring that is fixed to anouter ring member; a second seal ring that is fixed to an inner ringmember capable of relatively, coaxially rotating with respect to theouter ring member; and a magnetic sensor that is attached to the firstseal ring, wherein the second seal ring includes: a metallic ring thatis engaged with an outer circumference of the inner ring member; a lipthat is bonded to the metallic ring, and comes into contact with thefirst seal ring; and a pulser ring that is provided in the metallic ringso that the pulser ring can be opposed to the magnetic sensor in theradial direction and is detected by the magnetic sensor, wherein thepulser ring includes: an annular core portion that includes an innercylindrical portion provided on an outer circumference of the metallicring, an outer cylindrical portion arranged coaxially with the innercylindrical portion, and an annular plate portion for connecting theinner cylindrical portion with the outer cylindrical portion; and amultipolar magnetic rotor, in which N-poles and S-poles are alternatelyarranged in the circumferential direction, and which is bonded to theouter cylindrical portion.
 2. A sealing device according to claim 1,wherein the lip is made of rubber or resin.
 3. A sealing deviceaccording to claim 1, wherein the multipolar magnetic rotor is made ofmaterial on the basis of rubber or resin containing magnetic powder. 4.A sealing device according to claim 1, wherein the inner cylindricalportion and the outer cylindrical portion are arranged inside the widthin an axial direction defined by the first and the second seal ring. 5.A sealing device according to claim 1, wherein a portion of themultipolar magnetic rotor fills a gap formed between the annular coreportion and the metallic ring.
 6. A rotary detector comprising: a sensorassembling body that is fixed to a outer ring member; and a pulser ringthat is fixed to an inner ring member capable of relatively, coaxiallyrotating with respect to the outer ring member, is to be detected by thesensor assembling body, and is opposed to the sensor assembling body inthe radial direction, wherein the sensor assembling body includes: anannular ring that includes a cylindrical portion; a magnetic sensor thatis molded out of an outer body made of resin, and is arranged at apredetermined position on a outer circumferential side of thecylindrical portion; and a window that is opened in a radial directionand is formed in a region of the metallic ring corresponding to theregion in which the magnetic sensor is arranged.
 7. A rotary detectoraccording to claim 6, wherein the pulser ring includes: an annular coreportion having a cylindrical portion; and a multipolar magnet rotor thatis bonded to an outer circumference of the cylindrical portion of theannular core portion and is opposed to the magnetic sensor in the radialdirection.
 8. A rotary detector according to claim 6, wherein the sensorassembling body is press-fitted onto an inner circumferential face ofthe outer ring member, and the pulser ring is press-fitted onto an outercircumferential face of the inner ring member.
 9. A rotary detectoraccording to claim 6, wherein the magnetic sensor is exposed from theresin outer body, and one face of the magnetic sensor is on the sameface as the face of the window.
 10. A sealing device comprising: a firstseal ring that is fixed to an outer ring member; a second seal ring thatis fixed to an inner ring member capable of relatively, coaxiallyrotating with respect to the outer ring member; and a magnetic sensorthat is attached to the first seal ring, wherein the second seal ringincludes a pulser ring that is detected by the magnetic sensor and isprovided in the metallic annular ring so that the second seal ring canbe opposed to the magnetic sensor in a radial direction, wherein thepulser ring includes: an annular core portion attached to an outercircumference of the second seal ring; and a multipolar magnetic rotorprovided on an outer circumferential face of the cylindrical portion ofthe annular core portion, and wherein N-poles and S-poles arealternately arranged in the multipolar magnetic rotor in acircumferential direction, and the multipolar magnetic rotor emits linesof magnetic force, which loop between the magnetic poles, in the radialdirection onto the magnetic sensor side.
 11. A sealing device accordingto claim 10, wherein M-poles and S-poles are alternately formed andarranged in the circumferential direction of the multipolar magneticroller by magnetizing a base of rubber or resin containing magneticpowder in the radial direction of the multipolar magnetic rotor.
 12. Asealing device comprising: a first seal ring that is fixed to an outerring member; a second seal ring that is fixed to an inner ring membercapable of relatively, coaxially rotating with respect to the outer ringmember; and a magnetic sensor that is attached to the first seal ring,wherein the second seal ring includes: a metallic ring that is engagedwith an outer circumference of the inner ring member; a lip that isbonded to the metallic ring, and comes into contact with the first sealring; and a multipolar magnetic rotor that is provided in the metallicring so that the multipolar magnetic rotor can be opposed to themagnetic sensor in the radial direction, wherein the multipolar magneticrotor includes N-poles and S-poles alternately arranged in thecircumferential direction, a space being formed between the multipolarmagnetic roller and the first seal ring in the radial direction.
 13. Asealing device according to claim 12, wherein the second seal ringincludes an annular core portion engaged with an outer circumference ofthe metallic ring, and the multipolar magnetic rotor is bonded to anouter circumference of the annular core portion.
 14. A sealing deviceaccording to claim 12, wherein the multipolar magnetic rotor and the lipare separately formed.